1. Field of the Invention
The invention relates to a method for the production of a lost-foam casting model for a light metal cylinder liner of internal combustion engines.
2. The Prior Art
It is known to cast light metal cylinder liners having an elevated silicon content in engine blocks, using the composite casting method. In this connection, it is necessary to produce a good connection, either as a positive lock or in terms of material, between the base material having a lower Si content and the cylinder liner having a higher Si content. A prerequisite for such locking together of the cylinder liner and the base material is, among other things, a rough, fissured surface of the cylinder sleeve that is to be cast into place.
In order to produce this rough and fissured surface, different methods have already been proposed: blasting, milling of depressions, or reshaping of the surface of the cylinder liner by means of pressure rollers. It is known from European Patent Application No. 0 532 331 to work notches into the surface of a cylinder lining when producing it, using a rolling method or a casting method. All of the methods require another processing step subsequent to the production of the cylinder liner by means of casting technology.
It is furthermore known from German Patent No. DE 3909521 to produce cylinder liners using the lost-foam method. In this connection, the lost-foam casting model is produced in a multi-part mold, whereby the outside surface of the model remains unstructured.
It is known from German Patent No. DE 19958185, which is not a prior publication, to produce a lost mold, more precisely a lost-foam casting model, having a structured outside surface, in that particles are applied adhesively to the smooth surface of a lost mold, which particles produce undercuttings when the light metal cylinder liner is cast.